The present invention relates to linear accelerators and more particularly to a system for the conditioning of linear accelerators utilized in radiotherapy equipment.
Linear accelerators are the core of a radiotherapy device. A linear accelerator is used to produce high energy electrons for tumors, either through a x-ray or through direct application of the electrons to the tumor. The function of the accelerator is to accelerate electrons by feeding electromagnetic waves onto a structure made of, for example, copper to boost the energy of the electrons provided therefrom.
Prior to the use of such an accelerator, there is a requirement that conditioning occur to ensure the proper operation of the radiotherapy device. Conditioning is required because an undesirable characteristic of using such a device is that initially if there is a high field applied to the surface of the copper, electrons will be released from that surface. With this release of electrons arcing can occur, or a dark current is produced inside the accelerator that can affect its performance.
Accordingly, conventionally the accelerator is conditioned manually by an operator. Typically, the operator will manually adjust the high energy field provided to the accelerator from a low value to a high value in a gradual and controlled manner to condition its surface. The high energy field is increased to a level that is above the desired high energy field and then lowered to ensure that the accelerator is operating in an appropriate manner.
The problem with this approach is that an operator is required to monitor the conditioning parameters and change them until the accelerator is conditioned to handle the full power required. This operator control creates two problems. One is that the performance of the accelerator is highly dependent upon the skill of the operator. Therefore, the consistency associated with conditioning is erratic and is dependent upon the particular operator that is using it. Also, this manual process, even when a skilled operator is controlling the conditioning, can require a considerable amount of time.
Secondly, through such a system the detailed history of the process of conditioning is not automatically recorded. Lack of such detailed records impedes the implementation of a tight quality control system for the manufacturing of such accelerators.
Accordingly, what is desired is a system and method which will allow for improved consistency in the conditioning of the accelerator as well as a more cost effective alternative to the manual process as above described. In addition, the system should provide a record for the history of the conditioning of the accelerator. Thus, a better quality control system can be implemented. The system should be easy to implement, should be cost effective and should not add a substantial complexity to the existing systems that are presently available. Accordingly, what is needed is a system and method for conditioning an accelerator in a manner that overcomes the above-mentioned problems. The present invention addresses this need.
A method and system for automatically conditioning a linear accelerator is disclosed. The method and system comprise measuring the global variables of the accelerator and evaluating a plurality of events based upon the measurement of the global variables in which events has a hierarchy of importance. Finally, the method and system includes performing an action in response to the hierarchy of importance of the plurality of events.
Accordingly, a system and method in accordance with the present invention allows an accelerator to be conditioned unattended. The system and method in accordance with the present invention combines software and hardware to measure global variables and modifies the condition of the accelerator based upon those variables. Through the use of a system and method in accordance with the present invention conditioning can proceed in small systematic steps, thereby resulting in better-conditioned accelerators. Accordingly, an improvement in both the performance and longevity of the accelerator is possible due to the reduction in arcing and dark current. Finally a significant savings in the overall costs will result from the utilization of a system and method in accordance with the present invention.